CsrA protein explained

Symbol:	CsrA
CsrA
Pfam:	PF02599
Interpro:	IPR003751

Carbon storage regulator A (CsrA) is an RNA binding protein. The CsrA homologs are found in most bacterial species, in the pseudomonads they are called repressor of secondary metabolites (RsmA and RsmE).^[1] The CsrA proteins generally bind to the Shine-Dalgarno sequence of messenger RNAs and either inhibit translation or facilitate mRNA decay.^[2]

CsrA has a regulatory effect on glycogen biosynthesis and catabolism, glycolysis,^[2] biofilm formation^[3] and quorum sensing.^[4]

Interactions

The CsrA protein binds to a Stem-loop RNA motif. The ability of the protein to inhibit translation of bound mRNAs can be countered by the expression of sRNAs such as CsrB, CsrC, RsmZ, RsmY and RsmX that contain multiple copies of the RNA motif. These RNAs sequester CsrA, which allows the translation of the previously inhibited bound mRNAs. A study investigating specific binding of CsrA in the Salmonella transcriptome has identified 467 binding sites.^[5]

Notes and References

1. Timmermans. J. Van Melderen. L. Post-transcriptional global regulation by CsrA in bacteria.. Cellular and Molecular Life Sciences. Sep 2010. 67. 17. 2897–908. 20446015. 10.1007/s00018-010-0381-z. 23366724. 11115721.
2. Liu. MY. Gui. G. Wei. B. Preston JF. 3rd. Oakford. L. Yüksel. U. Giedroc. DP. Romeo. T. The RNA molecule CsrB binds to the global regulatory protein CsrA and antagonizes its activity in Escherichia coli.. The Journal of Biological Chemistry. Jul 11, 1997. 272. 28. 17502–10. 9211896. 10.1074/jbc.272.28.17502. free.
3. Jackson. DW. Suzuki. K. Oakford. L. Simecka. JW. Hart. ME. Romeo. T. Biofilm formation and dispersal under the influence of the global regulator CsrA of Escherichia coli.. Journal of Bacteriology. Jan 2002. 184. 1. 290–301. 11741870. 10.1128/jb.184.1.290-301.2002. 134780.
4. Sonnleitner. E. Romeo. A. Bläsi. U. Small regulatory RNAs in Pseudomonas aeruginosa.. RNA Biology. Apr 2012. 9. 4. 364–71. 22336763. 10.4161/rna.19231. free.
5. Holmqvist E, Wright PR, Li L, Bischler T, Barquist L, Reinhardt R, Backofen R, Vogel J . Global RNA recognition patterns of post-transcriptional regulators Hfq and CsrA revealed by UV crosslinking in vivo. . EMBO J . 2016 . 27044921 . 10.15252/embj.201593360 . 35 . 9 . 991–1011. 5207318 .